Background. To describe functioning and health of lymphedema patients and to identify their most common problems using the International Classification of Functioning, Disability and Health (ICF) as part of the preparatory studies for the development of ICF Core Sets for lymphedema. Methods. Cross-sectional study in a population of lymphedema patients (n = 200), undergoing treatment in a Dutch lymphedema-specialized hospital. The second-level categories of the ICF were used to collect information on patients' problems in daily functioning. Results. The mean age of the study group was 56 years (22-84). In total 78.5% of the patients were female. The most frequent mentioned items were: In the Body Functions component: muscle power and mobility of joints, in the Activities and Participation component: doing housework, and changing and maintaining a body position, in the Environmental Factors: Health professionals, who can act as both facilitators and barriers. Interestingly, patients assessed their health more positively than health professionals do. Conclusion. By using the ICF, a considerable part of the broad spectrum of problems in functioning of lymphedema patients was reported.